Cannot display measure in chart

How do i see the format of my measure? 

I use this code to create the measure. 

DurationTime = 
// Duration formatting 
// * @konstatinos 1/25/2016
// * Given a number of seconds, returns a format of "hh:mm:ss"
//
// We start with a duration in number of seconds
VAR Duration = Sum(PackML_EventLog_time_calculation[TimeInStepSec]) 
// There are 3,600 seconds in an hour
VAR Hours =
    INT ( Duration / 3600)
// There are 60 seconds in a minute
VAR Minutes =
    INT ( MOD( Duration - ( Hours * 3600 );3600 ) / 60)
// Remaining seconds are the remainder of the seconds divided by 60 after subtracting out the hours 
VAR Seconds =
    ROUNDUP(MOD ( MOD( Duration - ( Hours * 3600 );3600 ); 60 );0) // We round up here to get a whole number
// These intermediate variables ensure that we have leading zero's concatenated onto single digits
// Hours with leading zeros
VAR H =
    IF ( LEN ( Hours ) = 1; 
        CONCATENATE("0"; Hours); CONCATENATE (""; Hours ) )
// Minutes with leading zeros
VAR M =
    IF (
        LEN ( Minutes ) = 1;
        CONCATENATE ( "0"; Minutes );
        CONCATENATE ( ""; Minutes )
    )
// Seconds with leading zeros
VAR S =
    IF (
        LEN ( Seconds ) = 1;
        CONCATENATE ( "0"; Seconds );
        CONCATENATE ( ""; Seconds )
    )
// Now return hours, minutes and seconds with leading zeros in the proper format "hh:mm:ss"
RETURN
    CONCATENATE (
        H;
        CONCATENATE ( ":"; CONCATENATE ( M; CONCATENATE ( ":"; S ) ) )
    )